Alison Riske pulled off a major shock at the US Open, booking her place in the fourth round with a 6-3 6-0 win over Petra Kvitova.

Riske picked up the first break of the match in the fifth game of the first set and gave Kvitova little chance to recover the early deficit.

The unseeded American went on to break Kvitova again in the ninth game of the set to win it 6-3 in just over half an hour.

Any hopes that the number seven seed had of launching a comeback in the second set soon evaporated after Riske held her serve before breaking Kvitova at the fourth time of asking in the second game.

Riske had little trouble holding onto her own serve, but the same could not be said for Kvitova, who squandered a number of game points and allowed Riske to break her again in her next two service games to take the second set 6-0.

Riske's win means that she will face either Julia Glushko or Daniela Hantuchova in the next round.